*Dr Denes Molnar (Purdue University, USA)*

### Self-consistent viscous phase space distributions from kinetic theory

The main challenge is to describe how local phase space distributions are modified compared to their local equilibrium form in the presence of gradiens and dissipation in the system. In fact, an infinite class of phase space distributions can describe the same hydrodynamic fields. We advocate a self-consistent approach that obtains phase space corrections from relativistic kinetic theory. A both self-consistent shear viscous and bulk viscous phase space corrections calculated for a many component gas of hadrons will be presented and discussed how the corrections affect experimental observables.

*Ludwik Turko (IFT)*

### Finite size effects, intermolecular forces and effective virial expansion

A thermodynamically self-consistent model of quantum gas with the effective collective interaction will be presented

*Valeriya Mykhaylova (IFT)*

### Transport coefficients of Yang-Mills plasma

OTHER LECTURE, OTHER SUBJECT - beyond this nothing has been changed :-) LT in 2 weeks In the relaxation time approximation, the ratio of the bulk to the shear viscosities is discussed. A recent study including the Gribov parameter exhibits that this ratio goes like what is predicted in the AdS/CFT approach, even at very high temperature. We aim for a better understanding of this result.

*Dr David Alvarez-Castillo (JINR Dubna)*

### Compact star tidal deformability constraints from the GW170817 event and their impact on the equation of state

The method of estimation of tidal deformabilities of compact stars and present results for pure hadronic as well as hybrid stars that include the mass twins case will be presented. Then the recent GW170817 compact star tidal deformability constraints that serve to estimate radius values related to the stiffness of compact star matter will be analyzed.

*Dr Gábor Balassa (Wigner Research Centre for Physics, Hungarian Academy of Sciences)*

### Non-equilibrium Charmonium dynamics in heavy-ion collisions

The masses of the low lying charmonium states, shifted downwards due to the second order Stark effect. In pbar Au collisions at 6−10 GeV we study their in-medium propagation.The time evolution of the spectral functions of these charmonium states are studied with a Boltzmann Uehling-Uhlenbeck (BUU) type transport model. The in medium mass shift of these states can be observed in the dilepton spectrum, therefore, by observing the dileptonic decay channel of these low lying charmonium states, especially for PSI(3686), one can gain information about the largeness of the gluon condensate in nuclear matter. The methods used to calculate the elementary cross sections with charmonium in the final states are also discussed.

* UNUSUAL TIME and PLACE! Prof. Marek Gazdzicki (UJK Kielce and Frankfurt Univ.)*

### On Transitions in High Energy Nuclear Collisions; News from NA61/SHINE at CERN SPS

NA61/SHINE is a fixed target experiment at the CERN SPS. The main goals of the experiment is to discover the critical point of hadronic matter and to study the properties of the onset of deconfinemnt. Prof. Gazdzicki is the spokesperson of the NA61/SHINE Collaboration.

*prof. Jan Rafelski (Tuscon University, AZ, USA)*

### Time Evolution of Hot Hagedorn Universe

The task: connect the present day visible Universe with prior eras, back to primordial conditions at and above Hagedorn temperature, the point of creation of matter as we know it. Matter and antimatter emerged from Quark_Gluon Plasma when the Universe was 13 microseconds old. A nano-fraction surplus of matter survives the ensuing annihilation process. A dense electron positron-photon-neutrino plasma evolves. Electrons and positrons annihilate while neutrinos decouple. All this takes less than a second, this creates the context for the big-bang nucleo-synthesis and ultimately leads to the visible Universe around us. The continuous evolution across many evolutionary eras will be discussed and the Universe energy composition across cosmological history illustrated.

*Dr Marek Szczepanczyk (LIGO Scientific Collaboration/Embry-Riddle Aeronautical University, USA)*

### UNUSUAL DAY Gravitational Waves Core-Collapse Supernova Science with Advance and Third Generation Interferometers

Core-Collapse Supernovae(CCSNe) are the spectacular and violent deaths of massive stars. The study of Gravitational Waves (GW) from CCSNe give us information about the physical properties of the collapsed core and elucidate the explosion mechanism and can help elucidate the explosion mechanism as well unknown physics (silent supernovae or quark stars). I will review the state-of-art techniques used to search for GW from CCSNe and current work on detection perspectives with future GW Observatories. The reconstruction of the waveform and extraction of physical information is a difficult task. It requires a deep understanding of multi-dimensional CCSN simulations, data analysis caveats, detector response, as well as understanding how insights provided by neutrino and electromagnetic messengers help us extract GW signals from the detector noise. In the LIGO/Virgo Supernova Working Group we work on all aspects leading to direct detection of GW from CCSN and extracting physical information. I will talk about properties of the CCSN waveforms, their deterministic and non-deterministic components, algorithm development that uses the deterministic features (like g-modes) used to increase the visible distance for CCSN detection. I will also review the detection range, future algorithm developments and detection capabilities with the designs of future detector configurations.

*Michał Marczenko - IFT*

### Net-baryon number fluctuations in the quark-meson-nucleon model at finite baryon density

One of the most significant aspects of QCD thermodynamics is understanding how the transition from hadrons to their constituents—quarks and gluons—relates to the underlying deconfinement and chiral dynamics. This is of major relevance for heavy-ion collisions, as well as in the study of cold and dense systems, such as compact stars. The latter, however, is often studied exclusively in models of either hadron or quark degrees of freedom. In this talk, we present the mean-field thermodynamics of an effective hybrid quark-meson-nucleon (QMN) model for QCD phase transitions at low temperatures and finite baryon densities. In this framework, the chiral dynamics is described within the linear sigma model, whereas the deconfinement transition is driven by a medium-dependent modification of the particle distribution functions, where an additional scalar field is introduced. The structure of the net-baryon number fluctuations along with its higher order cumulants is discussed as possible probes for the chiral and deconfinement phase transitions. A qualitative comparison of the results obtained in the nucleonic (parity doublet) and quark (NJL) models is also presented.

*Dr Heiko Moller (Uniwersity of Darmstadt)*

### Evolution of intermediate-mass stars

In this talk, an overview of evolution and fate of stars from a numerical modeling perspective will be presented. Particular focus will be put on stars ranging between 8 to 12 times the mass of the sun. These stars are of great interest in stellar physics, as they denote the transition region of the less massive stars that end their lives as White Dwarfs and the massive stars that become gravitationally unstable, explode in a core-collapse supernova and either become a Neutron star or a Black Hole. Recent investigations indicate that the fate of intermediate-mass star is very sensitive to uncertainties of occurring nuclear reactions. We show that the temporal evolution in the stellar core is significantly altered by the occurrence of beta-decay and electron-capture processes on nuclei in the sd-shell.

*On Monday!!! - Prof. Teiji Kunihiro (Kyoto Univ.)*

### On Monday!!! Precursory Phenomena of QCD Phase Transitions in Hot and Dense Matter

The talk consists of two parts. In the first part, I discuss possible scenarios of the way how chiral restoration manifest itself in the spectral functions in hadron channels, partly based on our recent work (P.Gubler, T.K. and S.H.Lee, PLB767(2017),336. The second part is devoted to clarifying the nature and the properties of the soft mode of the QCD Z2 critical point(CP) on the basis of the functional renormalization group method (FRG). It is shown that the spectral function in the scalar channel shows a tachyonic behavior at finite momenta prior to the CP, which is interpreted to suggest that the assumed equilibrium state is unstable toward a stated with an inhomogeneous chiral condensate. This part is based on the following two papers by the same authors: T.Yokota, T.K. and K.~Morita, PTEP(2016) no.7, 073D01; arXiv:1707.05520 [hep-ph].

*Dr Elizaveta Nazarova (Lomonosov Moscow State University)*

### Event-by-event Elliptic Flow Fluctuations in PbPb collisions at sqrt{s_NN} = 5.02 TeV with CMS detector

Event-by-event elliptic flow harmonic distributions p(v_2) are measured in PbPb collisions at sqrt{s_NN} = 5.02 TeV using the CMS detector for the integrated p_T range 0.3 < p_T < 3.0 GeV/c and pseudorapidity range |eta|<1.0 . In order to gain insight on the nature of the initial geometry fluctuations, cumulant flow harmonics are calculated from the moments of the v_2 probability distribution p(v_2). A fine-level splitting between the higher-order cumulants is observed. The skewness with respect to the reaction plane is estimated from the cumulants and found to be negative, which suggests a non-Gaussian nature for the initial-state fluctuations, as predicted by hydrodynamic models. These observations suggest a non-Gaussian nature of the initial-state fluctuations. Furthermore, assuming that the flow harmonics are linearly proportional to the initial-state eccentricities, the p(v_2) distributions are fitted using an elliptic power law parametrization to study the initial-state geometry fluctuations.

*Dr Harri Niemi (Frankfurt University)*

### Transient relativistic fluid dynamics from the Boltzmann equation

A general derivation of relativistic fluid dynamics from the Boltzmann equation using the method of moments will be presented. The main difference between the presented approach and the traditional 14-moment approximation by Israel and Stewart is that we will not close the fluid-dynamical equations of motion by truncating the expansion of the distribution function. Instead, we keep all the terms in the moment expansion and truncate the exact equations of motion for the moments according to a systematic power counting scheme in Knudsen and Reynolds number. We show that the Boltzmann equation contains an infinite number of microscopic time scales and demonstrate that, in order to derive the fluid-dynamical equations of motion, it is essential to consider only the slowest of these time scales. We further test the validity of different approximations by comparing to the direct numerical solutions of the Boltzmann equation.

*Prof. Georg Wolschin (University Heidelberg)*

### Bottomia physics at RHIC and LHC energies

The suppression of Y mesons in the hot quark-gluon medium (QGP) versus reduced feed-down is investigated at energies reached at the Relativistic Heavy Ion Collider RHIC and the Large Hadron Collider LHC. Our centrality- and p_T-dependent model encompasses screening, collisional damping and gluodissociation in the QGP. For the Y(1S) ground state it is in agreement with both STAR and CMS data provided the relativistic Doppler effect and the reduced feed-down from higher states are properly considered. At both energies, most of the Y(1S) suppression is found to be due to reduced feed-down, whereas most of the Y(2S) suppression is caused by hot-medium effects. The importance of the latter increases with energy. The p_T-dependence is flat due to the relativistic Doppler effect and reduced feed-down. Results for PbPb at 5.02 TeV are predicted and compared with recent LHC run 2 preliminary data.

*Dr Jakub Jankowski (IFT)*

### Real time dynamics, phase transitions and holography

Recent results concerning the dynamics of holographic systems exhibiting various types of phase transformations will be reviewed - with a particular focus on first order transitions. The existence of the spinodal region will be demonstrated within linear and nonlinear response theory. The applicability of hydrodynamics in the critical region of the phase diagram would be discussed.

*Prof. I. Dadic (1 Rudjer Bovskovi'c Institute, Zagreb, Croatia)*

### Causality and Renormalization in Finite-Time-Path --- Out-of-Equilibrium $phi^3$ QFT

We use the retarded/advanced basis of out-of-equilibrium Green functions. We use the dimensional regularization method and find the correspondence of diverging contributions in the Feynman diagrams and their counterparts in R/A basis.

*Konstantin Maslov, NRNU (MEPhI) Moscow*

### A method of stiffening the relativistic mean-field (RMF) equation of state and its application to the description of neutron stars

It will be shown a way to make a given RMF equation of state for hadronic matter stiffer at high densities, while leaving it unchanged at lower densities. This method can be used to change the stiffness of either both isospin symmetric and asymmetric parts or only asymmetric part of the equation of state (EoS) in the RMF framework with field-dependent hadron masses and couplings. This allows to construct realistic phenomenological RMF models which are flexible enough to pass many experimental constraints.

*Prof. L.Turko, Dr. P.Huovinen, Mr. A.Dubinin*

### Three generations view on quark matter

Based on personal attendance in the last Quark Matter Conference – Chicago 2017 – review of recent progress/digress of research and understanding in the field of dense hadronic matter will be presented.

*dr Adam Smetana (Institute of Experimental and Applied Physics, CTU in Prague)*

### Role of neutrinos in the electroweak symmetry breaking

The condensation of known fermions is an appealing idea for explaining the electroweak symmetry breaking (EWSB) already since early eighties. It is natural to treat the top-quark condensate as the only non-negligible source of EWSB as the top quark dominates the fermion mass spectrum. However many realistic models of this kind have failed in reproducing the correct spectrum of masses of the top-quark and of the W, Z and Higgs bosons. We study the role of neutrino condensation. If a seesaw mechanism applies for the neutrino masses, the Dirac mass and the corresponding neutrino condensate may be significantly strong source of the electroweak symmetry breaking comparable to that of top-quark. Within the simplistic model we show that the number of right-handed neutrinos needed for meeting phenomenological requirements is very large, O(100).

*Dr Pok Man Lo (IFT)*

### CANCELLED: S-matrix approach to quantum virial expansion

THIS SEMINAR IS POSTPONED ON A LATER TIME In this talk, we discuss the application of S-mat rix formalism to study higher virial coefficients for a quantum-mechanical system of hadrons. The virial expansion provides a convenient way to parametrize the equation of state of a many-body system. It expresses the partition function and various thermodynamic functions as a power series in the particle density. For a classical system (e.g. the van der Waals non-ideal gas), the coefficients of the expansion can be computed directly from the Hamiltonian using the standard Mayer cluster expansion. The quantum version of such expansion has been formulated by Dashen, Ma and Bernstein within the framework of S-matrix. This allows the exact calculation of the 2nd virial coefficient from the knowledge of phase shift. We shall review briefly how this formalism can be applied to describe system of hadrons in heavy ion collisions. Using the input of empirical phase shifts from hadron scattering experiments, the important physics of resonance widths, coupling strengths and unitary constraints are naturally incorporated, beyond the capability of the standard Breit-Wigner formulation. The extension to third (and higher) virial coefficients is more challenging. Here, we attempt a generalization of two-body phase shift and define an analogous physical quantity suitable for discussing N-body scatterings. We shall examine such generalized phase shift in details for a gas of pions.

*Members and fans of EPTh division *

### "Quo Vadis?" Where have we been, what have we done in 2016 and where will we go in 2017?

Group members report on their breakthrough ideas, most remarkable visits, publications and events organisation accomplished in 2016. They also mention what could not yet be achieved and what will be on the agenda in 2017. Rules: no more than 10' pp. Potential speakers/performers are kindly asked to contact LT and report about their readiness to present their microseminar.

*Members and fans of EPTh division *

### "Quo Vadis?" Where have we been, what have we done in 2016 and where will we go in 2017?

Group members report on their breakthrough ideas, most remarkable visits, publications and events organisation accomplished in 2016. They also mention what could not yet be achieved and what will be on the agenda in 2017. Rules: no more than 10' pp. Potential speakers/performers are kindly asked to contact LT and report about their readiness to present their microseminar.

*Dr Marcus Bluhm (North Carolina State U.) *

### Properties of strongly coupled quantum fluids

Strongly coupled quantum systems are realized in nature in various forms, reaching from compact stellar objects, over tiny droplets of hot Quark-Gluon Plasma, to ultra-cold atomic Fermi and Bose gases. These systems share some interesting features despite their apparent differences in size, temperature, density or field strengths. This talk will focus on the Quark-Gluon Plasma and ultra-cold Fermi gases, discuss the observed similarity in their transport behavior, notably their perfect fluidity, and present some recent developments toward a better understanding of both strongly coupled quantum fluids.

*K. Morita (Yukawa Institute of Theoretical Physics, Kyoto, Japan)*

### Omega-proton correlation in heavy ion collisions

The two-particle momentum correlation between the proton (p) and the Omega-baryon (Ω) in high-energy heavy ion collisions is studied to unravel the possible spin-2, S=-3, pΩ-dibaryon recently suggested by lattice QCD simulations.

*Mateusz Cierniak (IFT)*

### The Munczek-Nemirovsky model in different metrics.

The Munczek-Nemirovsky (MN) model is defined by a set of truncations which simplify the Dyson-Schwinger equation (DSE) of a quark propagator to a form that can be solved analytically. In general the DSE is a self-similar equation that is usually solved by numerical iteration. Unlike the analytical approach, the iterative method produces fractal patterns and naturally drives the MN model's quark mass gap into a low mass state in analogy (but still with qualitative difference) to asymptotic freedom. My initial calculations were done with respect to the Euclidean QCD generating functional and in this talk I compare them to the solutions obtained in the Minkowski metric.

*Prof. Andre Peshier (University of Cape Town, SA) *

### Tracing the QCD pressure

Being interested in how a strongly coupled system approaches asymptotic freedom, we re-examine existing precision lattice QCD results for thermodynamic properties of the gluon plasma in a large temperature range. We discuss and thoroughly test the applicability of perturbative results, on which grounds we then infer that the pressure and other bulk properties approach the free limit somewhat slower than previously thought, and we revise the value of the first non-perturbative coefficient in the weak-coupling expansion.

*Dr Aneta Wojnar (IFT)*

### Equilibrium and stability of relativistic stars in extended theories of gravity

Now, there is the correct day of this seminar - FRIDAY as usual! :-) The static, spherically symmetric equilibrium configurations in extended theories of gravity (ETGs) is studied. We show that the stellar structure in ETGs can be recast in a very generic form: i.e. one gets the generalization of the Tolman-Oppenheimer-Volkoff equations. A stability analysis is also performed with special focus on the particular example of scalar-tensor gravity.

*Prof. dr hab. David Blaschke (IFT)*

### Mott dissociation of pions and kaons in hot, dense quark matter

The Beth-Uhlenbeck approach to the description of meson bound state formation and dissociation in hot dense quark matter is generalized to the case of 2+1 flavors on the basis of the PNJL model. One unexpected finding is the appearance of an anomalous K+ bound state in medium which appears as a good candidate for explaining the "horn" effect for the K+/pi+ ratio as observed in the energy scan by the NA49 experiment and confirmed by STAR.

*Alaksiej Kachanovich (IFT) - ON THURSDAY!*

### Gluon background field approximation to Yang-Mills thermodynamics

We give an introduction to the Sasaki-Redlich model for Yang-Mills thermodynamics in the background field approximation. We show that in the second order with respect to gluon field fluctuations the partition function depends only on the traced Polyakov loop Phi. We solve the gap equation for Phi as a function of the temperature and compare the result with lattice QCD simulations. We discuss next steps beyond the Gaussian approximation which lead, e.g., to a temperature dependent gluon mass.

*Prof. Dietmar Ebert, Humboldt-University, Berlin*

### Phase transitions in hexagonal, graphen-like lattice sheets and nanotubes

This talk considers a class of (2+1)D schematic models with four-fermion interactions that are effectively used in studying condensed-matter systems with planar structure, and especially graphene. Symmetry breaking in these models occurs due to a possible appearance of condensates. Condensates as well as fermion-antifermion exciton bound states are calculated. Moreover, nanotubes with corresponding boundary conditions are considered and their relation with the effect of an applied external magnetic field is discussed. To study phase transitions, the effective potential for the nanotube model including effects of finite temperature, density and an external magnetic field is calculated. Finally, the phase structure of the nanotube model under the influence of the Aharonov-Bohm effect is considered.

*Niels-Uwe Friedrich Bastian (IFT)*

### Density functional theory for effective QCD equation of state

We introduce a thermodynamic consistent formulation to describe relativistic equations of state based on arbitrary density functionals. Based on this we investigate the possibility of a van-der-Waals like phase transition by introducing a density dependent excluded volume, to construct flexible QCD EOS with critical endpoint. Authors: Niels-Uwe Bastian, Mark Kaltenborn

*Dr Aleksei Ivanytskyi (Bogoliubov Institute for Theoretical Physics, Kiev, Ukraine)*

### A novel equation of state for nuclear and hadronic matter with induced surface tension

Short range particle repulsion is proven to be rather important property of the hadronic and nuclear matter equation of state. A novel approach is presented, based on the virial expansion for a multicomponent system with hard core repulsion. A contribution of surface tension induced by particle interaction is a principally new element of that approach. Applications of this equation of state to the description of hadronic multiplicities measured in A+A collisions, the nuclear matter phase diagram and to modelling neutron star interiors are discussed.

*prof. dr hab. David Blaschke (IFT)*

### Generalized Beth--Uhlenbeck formulas from the $Phi-$derivable approach in 2-loop approximation

A dense fermion system with strong two-particle correlations (bound and scattering states = composite bosons) is considered within the Phi-derivable approach to the thermodynamic potential. It is shown that in the two-loop approximation for the Phi-functional of this fermion-composite boson system important cancellations hold which are one key element in the proof that the thermodynamic potential takes the form of a generalized Beth-Uhlenbeck formula. The other element are generalized optical theorems. It is shown that generalized Beth-Uhlenbeck formulas also hold for the other thermodynamic functions (entropy, density) which all assume the generic form of an energy-momentum integral over a statistical distribution function multiplied with a unique spectral density. In the near mass-shell limit, contrary to naive expectations, the latter reduces not to a Lorentzian but rather to a so-called "squared Lorentzian" shape. The developed formalism extends the validity of the Beth-Uhlenbeck approach beyond the low-density limit. It includes the Mott-dissociation of bound states in accordance with the Levinson theorem and the selfconsistent backreaction of the correlations to the propagation of the elementary fermions.

*Dr. Vadim Dmitriev (Saratov State University)*

### Kinetic equation approach to massive vector boson production from vacuum within the inertial mechanism

The kinetic theory approach to describe the vacuum creation of vector bosons with dynamical mass is applied to a conformal cosmological model. We discuss this process as an additional source for the cosmic microwave background (CMB) radiation originating from the cosmological electroweak phase transition.

* dr Pok Man Lo (IFT)*

### Repulsive interactions and their effects on the thermodynamics III

Continuation: In this talk we compare two approaches in modeling repulsive interactions among hadrons: the excludedvolume approximation and the S matrix formalism. The latter provides a consistent treatment of broad resonances based on empirical scattering phase shifts. We shall apply these techniques to study the thermodynamics of the (πN∆) system, with a particular focus on the fluctuation of baryon charge in the thermal medium. Limitations of the methods in describing dense hadronic matter would be briefly discussed.

*Dr. Yuriy Karpenko (INFN and University of Florence),*

### Viscous hydro + cascade modeling of heavy ion collisions at \sqrt{s_{NN}} = 7.7-200 GeV

State-of-the-art 3D viscous hybrid model is applied to heavy ion collisions at RHIC Beam Energy Scan (BES) energy range \sqrt{s}=7.7...200 GeV. The model employs the hadron transport approach UrQMD for the early and late non-equilibrium stages of the reaction, and 3+1 dimensional viscous hydrodynamics for the hot and dense quark-gluon plasma stage. It includes the equation of motion for finite baryon number, and employs an equation of state with finite net-baryon density to allow for calculations in a large range of beam energies. The parameter space of the model is explored, and constrained by comparison with the experimental data for bulk observables from SPS and the phase I BES at RHIC. The favored parameter values depend on energy, but allow to extract the effective value of the shear viscosity coefficient over entropy density ratio \eta/s in the fluid phase for the whole energy region under investigation. The estimated value of effective \eta/s increases with decreasing collision energy, which may indicate that \eta/s of the quark-gluon plasma increases with increasing baryochemical potential \mu_B.

*dr Pok Man Lo (IFT)*

### Repulsive interactions and their effects on the thermodynamics II

Continuation: In this talk we compare two approaches in modeling repulsive interactions among hadrons: the excluded-volume approximation and the S-matrix formalism. The latter provides a consistent treatment of broad resonances based on empirical scattering phase shifts. We shall apply these techniques to study the thermodynamics of the (πN∆) system, with a particular focus on the fluctuation of baryon charge in the thermal medium. Limitations of the methods in describing dense hadronic matter would be briefly discussed.

*dr Pok Man Lo (IFT)*

### Repulsive interactions and their effects on the thermodynamics

In this talk we compare two approaches in modeling repulsive interactions among hadrons: the excluded-volume approximation and the S-matrix formalism. The latter provides a consistent treatment of broad resonances based on empirical scattering phase shifts. We shall apply these techniques to study the thermodynamics of the (πN∆) system, with a particular focus on the fluctuation of baryon charge in the thermal medium. Limitations of the methods in describing dense hadronic matter would be briefly discussed.

*prof. dr hab. David Blaschke (IFT) at 10:00!*

### The universal symmetry energy conjecture

The difference between the energy per nucleon in pure neutron matter and in symmetric nuclear matter (SNM) is called the (a)symmetry energy. It plays a key role when relating the equation of state in SNM as probed, e.g., in heavy-ion collisions, with the one that govern the structure and composition of neutron stars. We prove that the symmetry energy contribution to the neutron star equation of state (beta- equilibrium and charge neutrality) is a universal function of the density for densities above saturation, provided that the direct Urca cooling process is inhibited. Phenomenology of compact star cooling supports the fulfilment of this constraint.

*Juan M. Torres-Rincon (Subatech, IN2P3/CNRS, Universite de Nantes)*

### Revisiting the equation of state of hot matter using the Polyakov-Nambu-Jona-Lasinio model

The phase diagram is one of the key features of hot and dense matter. First-principles QCD calculations, like QCD on a lattice, only provide reliable knowledge in very limited regions of this diagram. A more global (but approximate) description of the thermal properties of QCD can be achieved through effective models, like the Polyakov-Nambu-Jona-Lasinio model. This model is able to map the whole phase diagram at finite temperatures and densities, but the standard equation of state at mean-field level, already at zero baryonic density, presents strong tensions with the results provided by lattice-QCD calculations. I revisit the foundations of the model and the calculation of the thermodynamic potential to improve the description of the equation of state and make it compatible with current lattice-QCD results.

*dr Thomas Klaehn (ITF)*

### QCD gap equations and fractal structures? A simple model study

QCD's gap equations are self-consistent by their very nature. A typical method to solve them is to iterate an initial guess to a stable solution. As it is well known that more than one solution exists the question arises how and whether we obtain the correct one. We present a simple model where all solutions can be obtained from solving a polynomial equation and compare with results from the iterative method. We show that the method provides an in principle infinite amount of further solutions. To understand this behaviour as a consequence of the iterative approach we discuss fractal properties of the gap equation.

*prof. dr hab. D. Blaschke (IFT)*

### Three-fluid hydro based event simulation for collisions at NICA and FAIR energies

I describe a new event generator that is based on a three-fluid hydrodynamics description of the early stage of the collision, followed by a particlization at the chemical freeze-out to join a UrQMD "afterburner" accounting for hadronic final state interactions and a GEANT simulation of the detector response. I present first results for the FAIR/NICA energy scan ($sqrt{s_{NN}}=4-11$ GeV) addressing the directed flow of protons and pions as well as the proton rapidity distribution for two model EoS, with and without a first order phase transition. The new program has the unique feature that it can describe a hadron-to-quark matter transition of first order which proceeds in the baryon stopping regime that is not accessible to previous simulation programs designed for higher energies and assuming transparency of the colliding nuclei.

*prof. dr hab. Ludwik Turko (IFT)*

### Particle in strong fields

Problems related to the description of particles bound by strong external fields are present on all levels of the theory - started from the classical, then quantum mechanical, then quantum field theoretical formulations. A number of new effects is then expected as spontaneous positron emission or an appearance of condensates. Short review of problems on different levels will be given.

*dr Viktor Begun (UJ Kraków)*

### Pion condensation as a solution of the LHC proton-pion puzzle

In this talk I will review the recent success of the non-equilibrium hadronization model in describing the LHC data from PbPb collisions at 2.76 TeV. This approach allows to describe the measured particle multiplicities and spectra in a very economic way. It further predicts Bose-Einstein condensation for pions. This intriguing possibility will be addressed in details for finite systems with the use of higher order moments of the multiplicity distribution.

*prof. dr hab. Ludwik Turko (IFT)*

### Cancelled: Particle in strong fields

Cancelled: Problems related to the description of particles bound by strong external fields are present on all levels of the theory - started from the classical, then quantum mechanical, then quantum field theoretical formulations. A number of new effects is then expected as spontaneous positron emission or an appearance of condensates. Short review of problems on different levels will be given. Cancelled

*1. Łukasz Juchnowski, 2. dr hab. Dariusz Prorok - IFT*

### 1. Nonequilibrium meson production in strong fields 2. Does the low p_T pion enhancement occur in Pb-Pb collisions at the LHC, really?

Ł.J.:I will briefly introduce a kinetic equation approach to nonequilibrium pion and sigma meson production in a time-dependent, chiral symmetry breaking field (inertial mechanism). Our investigation focuses on the low-momentum pion enhancement observed in heavy-ion collisions at CERN - LHC. In this preliminary study, we consider the inertial mechanism for nonequilibrium production of the sigma mesons and their simultaneous decay into pion pairs for two cases of sigma mass evolution. The resulting pion distribution shows a strong low-momentum enhancement. D.P.: Many data in the High Energy Physics are, in fact, sample means. It is shown that when this exact meaning of the data is taken into account and the most weakly bound states are removed from the hadron resonance gas, the acceptable fit to the whole spectra of pions, kaons and protons measured at midrapidity in central Pb-Pb collisions at $sqrt{s_{NN}} = 2.76$ TeV is obtained. Low $p_{T}$ pions and protons are reproduced simultaneously as well as $p/pi$ ratio. Additionally, correct predictions extend over lower parts of large $p_{T}$ data.

*Aleksandr Dubinin (IFT)*

### Mott-hadron resonance gas and lattice QCD thermodynamics

We (D.Blaschke, A.D., L.Turko) present an effective model for the generic behavior of hadron masses and phase shifts at finite temperature which shares basic features with recent lattice QCD results within the PNJL model for correlations in quark matter. On this basis we obtain the transition between a hadron resonance gas phase and the quark gluon plasma in the spirit of the generalized Beth-Uhlenbeck approach where the Mott dissociation of hadrons is encoded in the hadronic phase shifts. We find that the restriction to low-lying hadronic channels is justified by the rather low chiral transition temperature found in recent lattice QCD thermodynamics results.

*Michał Marczenko - IFT*

### Matching Hagedorn mass spectrum with Lattice QCD

Recent Lattice QCD studies suggest that there are missing resonances in the strange sector of the hadron resonance gas model. We show how an improved fit for the Hagedorn mass spectrum, consistent with lattice QCD data for both equation of state and fluctuations of conserved charges, can account for these missing resonances.

*Dr. Pasi Huovinen (Universitaet Frankfurt)*

### Dynamical freeze-out in event-by-event hydrodynamics

In hydrodynamical modeling of the ultrarelativistic heavy-ion collisions the freeze-out is typically performed at a constant temperature. The more physical choice is to use a criterion that freeze-out happens when the hydrodynamical expansion rate exceeds the scattering rate of particles. I'll show how this uncertainty in freeze-out criterion affects the anisotropies v_2 and v_3 in event-by-event calculations.

*Introduction to Heavy Ion Collisions and Matter under Extreme Conditions X*

### Quark Matter for pedestrians

This is the tenth seminar/lecture talk performed within the monographic lecture course run by D. Blaschke, K. Redlich, L.Turko & Co. The course is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC 2015.pdf

*Dr Pok Man Lo, University of Wroclaw*

### Introduction to Heavy Ion Collisions and Matter under Extreme Conditions IX

Lattice QCD for pedestrians: This is the eighth seminar/lecture talk performed within the monographic lecture course run by D. Blaschke, K. Redlich, L.Turko & Co. The course is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC 2015.pdf

* Prof. Ludwik Turko, IFT, University of Wroclaw*

### Statistical physics of excluded volume effects for hadrons

The effects of attractive and repulsive interactions among hadrons lead to excluded volumes occupied by the hadrons – as in the Van der Waals equation. The need for the consistent description of fluctuations and phase transition phenomena makes necessary to introduce chemical potentials and use statistical physics machinery. A recent progress in this field will be reported.

*Prof. dr hab. David Blaschke (IFT)*

### Generalized Beth--Uhlenbeck formulas from the $Phi-$derivable approach in 2-loop approximation

A dense fermion system with strong two-particle correlations (bound and scattering states = composite bosons) is considered within the Phi-derivable approach to the thermodynamic potential. It is shown that in the two-loop approximation for the Phi-functional of this fermion-composite boson system important cancellations hold which are one key element in the proof that the thermodynamic potential takes the form of a generalized Beth-Uhlenbeck formula. The other element are generalized optical theorems. It is shown that generalized Beth-Uhlenbeck formulas also hold for the other thermodynamic functions (entropy, density) which all assume the generic form of an energy-momentum integral over a statistical distribution function multiplied with a unique spectral density. In the near mass-shell limit, contrary to na"{i}ve expectations, the latter reduces not to a Lorentzian but rather to a so-called "squared Lorentzian" shape. The developed formalism extends the validity of the Beth-Uhlenbeck approach beyond the low-density limit. It includes the Mott-dissociation of bound states in accordance with the Levinson theorem and the selfconsistent backreaction of the correlations to the propagation of the elementary fermions.

*Dr Pok Man Lo, University of Wroclaw*

### Thermodynamics of Broad Resonances

In this talk we discuss the physics of the lightest resonances of QCD, i.e. the sigma and kappa mesons. These resonances are so broad that the standard Breit–Wigner dispersive analysis can not be applied. We motivate a theoretical analysis of the experimental phase shift data on pion-pion and pion-Kaon scattering. This allows us to explore the effects of broad resonances on thermodynamics. We also examine the role of chiral symmetry breaking in describing these phenomena by comparing different theoretical approaches, including the chiral effective model and lattice calculations.

*Prof. David Blaschke, IFT, University of Wroclaw*

### Introduction to Heavy Ion Collisions and Matter under Extreme Conditions VIII

This is the eighth seminar/lecture talk performed within the monographic lecture course run by D. Blaschke, K. Redlich, and L.Turko. The course is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC 2015.pdf

*Dr. Matthias Hempel, University of Basel, Switzerland*

### Clusters and phase transitions in the supernova EoS

The low density EoS of supernova matter is governed by the nuclear liquid-gas phase transition, that is also connected to cluster formation. At high densities, a phase transition to deconfined quark matter can occur. I will discuss some basic aspects of these two phase transition, how they can be implemented in supernova simulations, and the possible effects they can have on the supernova dynamics.

*Prof. David Blaschke, IFT, University of Wroclaw*

### Introduction to Heavy Ion Collisions and Matter under Extreme Conditions VII

This is the seventh seminar/lecture talk performed within the monographic lecture course run by D. Blaschke, K. Redlich, and L.Turko. The course is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC 2015.pdf

*Dr Jakub Jankowski,Jagiellonian University, Cracow*

### Conformal defects in Supergravity

We construct numerically gravitational duals of theories deformed by localized Dirac delta sources for scalar operators both at zero and at finite temperature. We find that requiring that the backreacted geometry preserves the original scale invariance of the source uniquely determines the potential for the scalar field to be the one found in a certain Kaluza-Klein compactification of 11D supergravity. This result is obtained using an efficient perturbative expansion of the backreacted background at zero temperature and is confirmed by a direct numerical computation. Numerical solutions at finite temperatures are obtained and a detailed discussion of the numerical approach to the treatment of the Dirac delta sources is presented. The physics of defect configurations is illustrated with a calculation of entanglement entropy.

*Prof. David Blaschke, IFT, University of Wroclaw*

### Introduction to Heavy-Ion Collisions and Matter under Extreme Conditions VI

This is the sixth seminar/lecture talk performed within the monographic lecture course run by D. Blaschke, K. Redlich. The course is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC-2015.pdf

*Prof. David Blaschke, IFT, Uniwersity of Wroclaw*

### Neutrino emissivities and bulk viscosity in neutral two flavor quark matter

We study thermodynamic and transport properties for the isotropic color-spin-locking (iso-CSL) superconducting quark matter phase under compact star constraints within a NJL-type chiral quark model. We present results for the iso-CSL direct URCA emissivities and bulk viscosities, which fulfil the constraints on quark matter derived from cooling and rotational evolution of compact stars.

*Prof. David Blaschke, IFT, University of Wroclaw*

### Introduction to Heavy-Ion Collisions and Matter under Extreme Conditions V

This is the fifth seminar/lecture talk performed within the monographic lecture course run by D. Blaschke, K. Redlich. The course is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC-2015.pdf

*Dr H. Grigorian. JINR Dubna, Russia*

### Cooling of neutron stars and hybrid stars with a stiff hadronic EoS

Within the "nuclear medium cooling" scenario of neutron stars all reliably known temperature - age data can be comfortably explained by a set of cooling curves obtained by variation of the star mass within the range of typical observed masses. The recent measurements of the high masses of the pulsars PSR J1614-2230 and PSR J0348-0432 on the one hand and the low masses for PSR J0737-3039B and the companion of PSR J1756-2251 on the other provide independent proof for the existence of neutron stars with masses in a broad range from 1.2 to 2 M⊙. The values M>2 M⊙ call for sufficiently stiff equations of state for neutron star matter. We investigate the response of the set of neutron star cooling curves to a stiffening of the nuclear equation of state so that maximum masses of about 2.4 M⊙ would be accessible and to a deconfinement phase transition from such stiff nuclear matter in the outer core to colour superconducting quark matter in the inner core. Without readjustment of cooling inputs the mass range required to cover all cooling data for the stiff DD2 equation of state should include masses of 2.426 M⊙ for describing the fast cooling of CasA while the existence of a quark matter core accelerates the cooling so that CasA cooling data are described with a hybrid star of mass 1.674 M⊙

*Prof. David Blaschke, IFT, University of Wroclaw*

### Introduction to Heavy-Ion Collisions and Matter under Extreme Conditions IV

This is the fourth seminar/lecture talk performed within the monographic lecture course run by D. Blaschke, K. Redlich. The course is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC-2015.pdf

*prof. D. Ebert, Humboldt-Universitaet, Berlin, Germany*

### Strong decays of vector mesons to pseudoscalar mesons in the relativistic quark model

Strong decays of vector mesons to pseudoscalar mesons are considered in the framework of the microscopic decay mechanism and the relativistic quark model based on the quasipotential approach. The quark-aniquark potential is employed as the source of the q-qbar pair creation. The calculated rates of strong decays of light and heavy-light mesons and heavy quarkonia agree well with available experimental data.

*prof. Ludwik Turko, IFT, University of Wroclaw*

### Introduction to Heavy-Ion Collisions and Matter under Extreme Conditions III

This is the second seminar talk performed within the monographic lecture course run by D. Blaschke, K. Redlich. The lecture is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC-2015.pdf

*Dr Olaf Kaczmarek, University of Bielefeld, Germany*

### Recent developments in Lattice QCD studies for transport coefficients and quarkonia in the QGP

I will report on a lattice investigation of heavy quark momentum diffusion within pure SU(3) plasma above the deconfinement transition, with quarks treated to leading order in the heavy mass expansion. We measure the relevant ``colour-electric'' Euclidean correlator and based on several lattice spacings perform the continuum extrapolation. This will allow for a determination of the relevant transport coefficient in the continuum. Furthermore new results for charmonium and bottomonium states in the QGP will be presented.

*prof. Ludwik Turko, IFT, University of Wroclaw*

### Introduction to Heavy-Ion Collisions and Matter under Extreme Conditions II

This is the second seminar talk performed within the monographic lecture course run by D. Blaschke, K. Redlich. The lecture is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC-2015.pdf

*dr Thomas Klähn, IFT - University of Wroclaw*

### Bag model revisited

The bag model is probably the most simple model to describe the equation of state of dense quark matter one can think of. A significantly more sophisticated approach to dense quark matter is provided by the Dyson-Schwinger formalism. I will explain briefly, how the bag model can be understood within this framework, what it misses and how it can be extended without loosing simplicity. I will make a few additional remarks regarding the 'standard' Maxwell phase transition construction and it's applicability.

*prof. Ludwik Turko*

### Introduction to Heavy-Ion Collisions and Matter under Extreme Conditions

This is the first of the monographic lecture course run by D. Blaschke, K. Redlich, L. Turko. The lecture is devoted to master students, PhD students and all interested in the subject. More details in: http://www.wfa.uni.wroc.pl/pub/content/3552/files/Introduction%20to%20Heavy-Ion%20Collisions%20and%20Matter%20under%20Extreme%20Conditions.pdf

*dr Chihiro Sasaki, Frankfurt Institute for Advanced Studies (FIAS), Germany*

### Charm fluctuations and chiral transition

Thermal fluctuations and correlations between the light and heavy-light mesons are explored within a chiral effective theory implementing heavy quark symmetry. We show, that various heavy-light flavor correlations indicate a remnant of the chiral criticality in a narrow range of temperature where the chiral susceptibility exhibits a peak structure. The onset of the chiral crossover, in the heavy-light flavor correlations, is therefore independent from the light flavors. This indicates that the fluctuations carried by strange charmed mesons can also be used to identify the chiral crossover, which is dominated by the non-strange light quark dynamics.

*Prof. dr hab. Ludwik Turko*

### The critical behavior of hadronic matter: a comparison of lattice and bootstrap model calculations

Hagedorn statistical bootstrap model and the related concept of the limiting temperature begun the discussion about phase transitions in the hadronic matter. This was also the origin of the quark-gluon plasma concept. We discuss here to which extend lattice studies of QCD critical behavior at non-zero chemical potential are comparable with the statistical bootstrap model calculations.

*Dr. Anatoly Panferov (Saratov State University)*

### Сomputer modeling of dynamic Schwinger effect: problems and opportunities

We consider the problem of pair creation in time-dependent strong external fields within a kinetic equation approach. Different types of time dependence of model laser pulses and their relation to the distribution function of produced particles are discussed. Special attention is paid to the subtleties of the numerical solution of the kinetic equation with time-dependent non-Markovian source term.

*prof. David Blaschke (JINR BLTP and Univ. Wroclaw, Poland) *

### Quantum flavor kinetics and chemical freeze-out

We present current status of a quantum kinetic formulation of the chemical equilibration process in dense hadronic matter at the hadronization transition. Delocalization of hadron wave functions at the Mott-Anderson transition (where their binding energies vanish) lead to a divergence of scattering lengths and critical enhancement of earrangement collisions between hadrons. We exemplify this for different meson-meson scattering processes from light (pi-pi scattering) to heavy flavors (charmonium dissociation). On this basis we suggest that chemical freeze-out has to be correlated with (partial) chiral symmetry restoration.

*mgr Łukasz Juchnowski - IFT UWr*

### The dynamical Schwinger effect in the electron-positron plasma

We study the dynamical Schwinger effect in the vacuum excitation of the electron-positron plasma under action of a "laser pulse" of the simplest configuration: a linearly polarized,time-dependent and spatially homogeneous electric field. Methodical basis of this investigation is the kinetic equation which is an exact consequence of the basic equations of motion of QED in the considered field model. In the present work we investigate some features of the residual electron- positron plasma and the transient process of its formation. Moreover we compare predictions on the basis of different WKB-type approximations with our results. Such a comparison demonstrates a considerable divergence results in strong non-stationary fields.

*Maciej Lewicki, Michał Naskręt - IFT UWr*

### Time projection chambers (TPC) in the experiment NA61/SHINE: 1.Calibration of TPC with pulser tool 2. Krypton calibration of TPC

1. The pulser tool is used to scan the electronic response of each pad in a TPC chamber. Sending a short electric pulse through all the pads can give us an information about an electronic gain and time delay. Therefore primary goal of the pulser calibration is to determine the time delay for each pad. In addition, the obtained data can be used for diagnostic purposes: finding dead pads, dead channels or front-end electronics. 2.Simulation of events in a TPC chamber through a decay of excited Krypton atoms gives us a spectrum, which is later fitted to the model spectrum of Krypton from a Monte-Carlo simulation. The data obtained in such a way serves us to determine malfunctioning electronics in TPC. Thanks to the krypton calibration we can determine channels and create a map of pad by pad gains. In my talk I will present an algorithm I developed and results I obtained for recent calibration runs.

*prof. dr hab. Ludwik Turko (IFT)*

### Particle in strong fields

Problems related to the description of particles bound by strong external fields are present on all levels of the theory - started from the classical, then quantum mechanical, then quantum field theoretical formulations. A number of new effects is then expected as spontaneous positron emission or an appearance of condensates. Short review of problems on different levels will be given.

*dr Kenji Morita (Yukawa Institute in Kyoto)*

### Lambda-Lambda interaction from relativistic heavy ion collisions

We discuss how to extract Lambda-Lambda interaction from relativistic heavy ion collisions. We present a theoretical framework to disentangle several sources of Lambda-Lambda correlation and comparison with STAR data.

*Dr David Edwin Alvarez Castillo *

### Supporting the existence of the QCD critical point by compact star observations

We present the argument that the observation of a gap in the mass-radius relationship for compact stars which proves the existence of a so-called third family (aka "mass twins") will imply that the $T=0$ equation of state of compact star matter exhibits a strong first order transition with a latent heat that satisfies $Deltaepsilon/epsilon_c > 0.6$. The observation of a disconnected branch (third family) of compact stars in the mass-radius diagram proves the existence of a CEP in QCD. Furthermore we show results of a Bayesian analysis (BA) using disjunct M-R constraints for extracting probability measures for cold, dense matter equations of state. In particular this study reveals that measuring radii of the neutron star twins has the potential to support the existence of a first order phase transition for compact star matter.

*Aleksandr Dubinin (IFT)*

### Mott-hadron resonance gas and lattice QCD thermodynamics.

We present an effective model for the generic behavior of hadron masses and phase shifts at finite temperature which shares basic features with recent developments within the PNJL model for correlations in quark matter. On this basis we obtain the transition between a hadron resonance gas phase and the quark gluon plasma in the spirit of the generalized Beth-Uhlenbeck approach where the Mott dissociation of hadrons is encoded in the hadronic phase shifts. We find that the restriction to low-lying hadronic channels is justified by the rather low chiral transition temperature found in recent lattice QCD thermodynamics results.

*Alexandra Friesen, JINR Dubna*

### Quark scattering off quarks and hadrons

The in-medium elastic scattering qq → qq, bar{q}q → bar{q}q and bar{q}bar{q} → bar{q}bar{q} is calculated within the two-flavor Polyakov-loop-extended Nambu-Jona-Lasinio model. The integral and differential quark-quark scattering, its energy and temperature dependence are considered and their flavor dependence is emphasized. The comparison with results of other approaches is presented. The consideration is implemented to the case of quark-pion scattering characterizing the interaction between quarks and hadrons in a kinetic multiphase treatment, and the first estimate of the quark-pion cross sections is given. A possible application of the obtained results to heavy ion collisions is shortly discussed.

*dr hab. Andrzej Wereszczyński (UJ)*

### Neutron stars and EoS of nuclear matter in the near-BPS Skyrme model

Using a low energy effective model of QCD - the near-BPS Skyrme model (which provides a very good description of nuclear binding energies) I will study neutron stars with the back reaction of gravity on the matter field fully taken into account. After fitting 2 parameters of the model in B=1 sector I will find neutron stars ($B_{max} sim 10^{57}$) with a very good agreement with observational data. I will compute EoS and show that nuclear matter becomes stiffer when mass of the star increases.

*Hong-Bo Deng (GSI, Bejing University)*

### Strong and EM decays of light and heavy-light meson in the effective chiral NJL model

Methods of calculations of transitions amplitudes for strong and electromagnetic decays of mesons within effective NJL model will be presented.

*multiauthors*

### flash seminars - change!

Important change: due to important organizational reasons this flash seminar is shifted by one day: from Wednesday to Thursday. Sorry for all inconveniences :-(. 1. Sanjin Benic: "The equation of state of dense and warm QCD matter" 2. Kenji Morita: "Net baryon number probability distribution near chiral phase transition" 3. Alex Kaltenborn: "Exotic Nuclear Shapes in the 'Pasta' Phase of Matter in Neutron Stars" 4. Oliver Hamil: "Braking index of rotating magnetized pulsars"

* Prof. David Blaschke, IFT, University of Wroclaw*

### Introduction to Heavy Ion Collisions and Matter under Extreme Conditions VIII

This is the eighth seminar/lecture talk performed within the monographic lecture course run by D. Blaschke, K. Redlich, and L.Turko. The course is devoted to master students, PhD students and all interested in the subject. More details in: http://panoramix.ift.uni.wroc.pl/pluginfile.php/10955/mod_resource/content/2/Monografic_Lecture_HIC 2015.pdf

* Michal Naskret*

### What is happening at CERN?

This is HoMPA seminar (prof. Kucharczyk/Dr. Klaehn) talk invited to be presented within Theory of Elementary Particles Division seminar. NB - no obligatory ties! We have all heard about the Large Hadron Collider experiment at CERN, but do we actually know what is happening there? Why is it important? Why there are two similar experiments at the Brookhaven National Laboratory and at the Joint Institute for Nuclear Research in Dubna? What happens when heavy ions collide? How can we describe heavy ion collisions[1]? What is the quark-gluon plasma and why is it important[2]? What is the hadron resonance gas model[3]? Why is the freeze-out interesting[4]? In my talk I will address all of those questions. I will also present my research topics [5] in the heavy ion collisions universe. References [1] J.I.Kapusta: "Finite- temperature field theory", CUP (1989). [2] K.Yagi, T.Hatsuda and Y.Miaki: "Quark-Gluon Plasma", CUP (2005). [3] J. Jankowski and D. Blaschke: "Chiral condensate in hadronic matter", PRD 87 (2013) 105018. [4] D. Blaschke, J. Berdermann, J. Cleymans and K. Redlich: "Chiral condensate and Mott-Anderson freeze-out", Few Body Syst. 53 (2012) 99. [5] D. Blaschke and M. Naskret, "Mott-Anderson freeze-out and the strange matter horn", in preparation (2014).

*Prof. David Blaschke*

### Towards a unified EoS for quark-hadron matter

A main problem to arrive at a unified EoS for quark-hadron matter is the description of the mass spectrum of hadrons as being strongly corrrelated multiquark states (cluster decomposition) and their in-medium modification including their dissociation due to the Mott effect. The formulation can be achieved in the form of a generalized Beth-Uhlenbeck EoS with medium dependent phase shifts describing the multiquark correlations. A generic ansatz, motivated by calculations within the PNJL model is introduced and first results are presented.

*mgr Łukasz Juchnowski*

### The dynamical Schwinger effect in the electron-positron plasma

We study the dynamical Schwinger effect in the vacuum excitation of the electron-positron plasma under action of a "laser pulse" of the simplest configuration: a linearly polarized,time-dependent and spatially homogeneous electric field. Methodical basis of this investigation is the kinetic equation which is an exact consequence of the basic equations of motion of QED in the considered field model. In the present work we investigate some features of the residual electron-positron plasma and the transient process of its formation. Moreover we compare predictions on the basis of different WKB-type approximations with our results. Such a comparison demonstrates a considerable divergence. results in strong non-stationary fields.

*Michal Sokolowski*

### Finding the Hybrid Equation of State

After a brief introduction to compact stars a simple class of hybrid equation of state (EoS) with three parameters is investigated concerning the mass-radius relationships of compact stars that will be predicted from it by solving the Tolman-Oppenheimer-Volkoff equations. First results of the Master Thesis project are presented and an outlook is given on how to find the most likely hybrid EoS by a Bayesian analysis of the results using available and future pulsar observations.

*Łukasz Juchnowski*

### Decoherence of strong EM field II

Continuation of the previous seminar

*Łukasz Juchnowski*

### Decoherence of strong electromagnetic field

For long period of time decoherence was absent in the studies of quantum physics. Hopefully H.D Zeh (1970s) and W. Zurek (1980s) found the connection between decoherence and the emergence of classicality in the quantum framework. Nowadays we know that decoherence is responsible for difficulties with observation of wave nature of matter. During the seminar we will discuss the decoherence of strong electromagnetic field as a consequence of pair production.

*Dr Tobias Fischer*

### The role of nuclear de-excitation in core collapse supernovae

I will explain the impact of neutrino-pair production from the de-excitation of highly excited heavy nuclei in core-collapse supernova simulations.

*Łukasz Juchnowski*

### Decoherence of strong EM field (part 2)

Continuation of the previous seminar.

*Łukasz Juchnowski*

### Decoherence of strong electromagnetic field II

Continuation of the previous seminar.

*Łukasz Juchnowski*

### Decoherence of the strong magnetic field II

Continuation of the previous seminar.

*Aleksandr Dubinin*

### Pion and sigma meson dissociation and modified PNJL model at finite temperature

We investigate the thermodynamics of two-particle correlations in a hot medium, with correlations in the pion, sigma meson interaction channels. Special emphasis is put on a correct description of the bound states’ dissociation in the vicinity and beyond the Mott temperature. This is achieved by evaluating the polarization functions for quark-antiquark (meson) correlations as a function of the temperature. The results can be represented by introducing modulus and phase of the complex propagator functions for these states. We study the effect of modeling confinement by a low-momentum cutoff in loop integrals on the behavior of the phase shifts. On this basis the thermodynamical potential and the equation of state for quark matter with meson correlations is evaluated in analogy to a Beth-Uhlenbeck equation.

*dr Thomas Klaehn*

### CompOSE - CompStar Online Supernovae Equations of State

CompOSE is an online database dedicated to equations of state which can be applied in astrophysical simulations of neutron stars, supernovae and other systems which are characterized by the presence of dense, hot or cold matter. A typical problem for this kind of repositories arises from the variety of possible data formats to store the data. CompOSE addresses this problem and suggests a unified data format which is able to account for all possible data that might be provided by the developers of new EoS. In order to connect to existing code which has been developed for different data formats interpolation routines are provide to use CompOSE's data table as an input to write new tables in any desired format suited to the needs of the potential user. The seminar will present these and a few other features of CompOSE in more detail.

*Rafał Łastowiecki*

### Implications of the measurement of pulsars with two solar masses for quark matter in compact stars and HIC. A NJL model case study

We will discuss the results of recently published study (Phys.Rev. D88 (2013) 085001, arXiv:1307.6996) of the NJL model parameter space in context of the mass measurement of heavy pulsars PSR J1614-2230 and PSR J0348- 0432. We will show that hybrid stars with quark cores are still a possibility and that such a measurement can serve as a strong constraint on allowed space of parameters for effective model.

*Ludwik Turko*

### New year 2013/2014 plans

The first this academic year meeting of the Division would be devoted to the summary of last activity, to the discussion about seminar's schedule and all that. Participants are expected to propose their talks - related, if possible, to the main Division's activity.

*Prof. dr hab. David Blaschke*

### Proving the existence of the QCD critical point by compact star observations

In order to prove the existence of a critical end point (CEP) in the QCD phase diagram it is sufficient to demonstrate that at zero temperature $T=0$ a first order phase transition exists as a function of the baryochemical potential $\mu$, since it is established knowledge from ab-initio lattice QCD simulations that at $\mu=0$ the transition on the temperature axis is a crossover. We present the argument that the observation of a gap in the mass-radius relationship for compact stars which proves the existence of a so-called third family (aka "mass twins") will imply that the $T=0$ equation of state of compact star matter exhibits a strong first order transition with a latent heat that s satisfies $\Delta\epsilon/\epsilon_c >0.6$ [Alford et al., arxiv:1302.4732]. Since such a strong first order transition under compact starconditions will remain first order when going to symmetric matter, this completes the argument that the observation of a disconnected branch (third family) of compact stars in the mass-radius diagram proves the existence of a CEP in QCD.

*dr. Thomas Klaehn, prof. David Blaschke*

### Hadron-Quark Crossover and Massive Hybrid Stars

Recently, Masuda et al. (arXiv:1212.6803) have elaborated on a method for constructing a hadron-to-quark matter transition suggested by them earlier (arXiv:1205.3612) which seemingly provides an approach to construct an equation of state that is very robustly stiff enough to allow hybrid stars with masses well above 2 solar masses. In the spirit of a journal club, we discuss this paper and the drawbacks implied by the suggested method by comparing with standard thermodynamics of phase transitions (Gibbs constructions). We invite all group members and interested audience to attend the seminar well-prepared for participating in the discussion.

*mgr Łukasz Juchnowski*

### Boltzmann-equation approach to pair production - further details

Some investigations show possibility of the $e^{+}e^{-}$ pair production from vacuum even in weaker than the critical but time-dependent electromagnetic fields. This process can be described by kinetic equation. Boltzmann equation approach gives opportunity to study transient vacuum responses for various laser beam parameters. Good understanding of this issue seems to be of great importance in astrophysics and heavy ion collision physics.

*prof. Ludwik Turko*

### Direct detection of an arrow of time – without CP violation help

Within our Journal Club activity recent result of the BABAR collaboration concerning time-reversal violation will be presented. Time reversal violation was observed till now through observation of CP violation in kaons and B meson decay using the CPT theorem. Recent BABAR study (archive: 1207.5832v3 hep-ex) of B meson decays allows for a direct observation of time-reversal violation without relying on CPT symmetries. This important and basic result is based on the entanglement of B0-antiB0 resulting from Upsilon Y(4s) meson (arxiv: 1203.0171 hep-ph).

*Łukasz Juchnowski*

### Decoherence of strong electromagnetic field

For long period of time decoherence was absent in the studies of quantum physics. Hopefully H.D Zeh (1970s) and W. Zurek (1980s) found the connection between decoherence and the emergence of classicality in the quantum framework. Nowadays we know that decoherence is responsible for difficulties with observation of wave nature of matter. During the seminar we will discuss the decoherence of strong electromagnetic field as a consequence of pair production.

*mgr Agnieszka Wergieluk*

### Role of the Levinson theorem for modeling pion dissociation in hot PNJL quark matter

Pion dissocation by the Mott effect in quark plasma is described within the generalized Beth-Uhlenbeck approach on the basis of a PNJL model which allows for a unified description of the bound, resonant and scattering states. As a first approximation, we utilize the Breit-Wigner ansatz for the spectral function and clarify its relation to the complex mass-pole solution of the pion Bethe-Salpeter equation. Describing the pion Mott dissociation as a spectral broadening of the pion bound state beyond T_Mott leaves out significant aspect: the continuum of scattering states. We utilize the Levinson theorem in order to specify a generic ansatz for the contribution from the scattering continuum and demonstrate its role for the thermodynamics of pion dissociation.

*mgr Rafał Łastowiecki*

### Shapiro delay measurement of a 2 solar mass neutron star

We will discuss techniques used in the mass measurements of distant astrophysical objects. In particular we will focus on binary system with pulsar PSR J1614-2230. The large, precisely measured mass of this object has been a source of intense discussion on constraining power of such observation, in particular on the possibility of appearance of exotic phases of matter in cores of neutron stars.

*Dr Thomas Klähn*

### From neutron stars to heavy ion collisions, and how to eliminate the asymmetry

Neutron stars are very asymmetric objects with respect to the isospin, e.g., the number of protons and neutrons differ largely. Consequently, the equation of state as the relation between (energy-)density and pressure will differ from that of fairly isospin symmetric matter as we find it in heavy ion collisions. As there is some hope to indirectly measure the neutron star EoS from mass and radius observations even, or in particular, at densities far beyond saturation the question arises, how significantly different these systems are and whether one could be able to give limits on the symmetric EoS at supersaturation assuming the NS EoS is known. I will present an idea we currently develop which might lead to a positive answer based on a few simple assumptions.

*mgr Jakub Jankowski*

### Towards holographic Quarkyonic matter

Large N QCD matter at intermediate baryon densities and low temperatures has been conjectured to be in so called Quarkyonic phase. It is to have quark Fermi sea and on top of it confined spectrum of excitations. Motivated by exotic features characterizing this phase we study properties of cold baryonic matter in N_f=1 Sakai-Sugimoto model searching for holographic realisation of Qyarkyonic matter. We use simplified mean field description and focus on regime of parametrically large densities of the order of square of 't Hooft coupling as they lead to interesting physical effects. One of the is the occurrence of modes breaking translational invariance which were found in the deconfined phase of the model and turn out to be absent here. Other completely new phenomenon are density enhanced meson-baryon interactions which significantly affect vector and axial vector meson spectrum allowing for a qualitative interpretation of mesons as collective excitations of the medium.

*dr Alvarez Castillo, Universidad Autonoma de San Luis Potosi, Meksyk*

### The Equation of State from Observed Masses and Radii of Neutron Stars

The paper by Steiner, Lattimer, and Brown will be reviewed and discussed within the "Journal Corner" programme of the seminar. The paper is available online http://arxiv.org/abs/1005.0811

*Ludwik Turko*

### Elementary Particle Theory - Division's and Seminar's plans

The first this academic year meeting of the Division would be devoted to the summary of last activity, to the discussion about seminar's schedule and all that. Participants are expected to propose their talks - related, if possible, to the main Division's activity.

*Łukasz Juchnowski*

### Dynamical Schwinger mechanism for pair production

I will discuss the Schwinger mechanism for the $e^{+}e^{-}$ pair production in the presence of a time-dependent external electric field. A review of the kinetic approach to this non-perturbative process will be presented. Some investigations show posibility of the $e^{+}e^{-}$ pair production even in weaker than the critical but time-dependent field.

*Dr Tomasz Partyka (Uniwersytet Jagielloński)*

### NONUNIFORM CHIRAL CONDENSATE IN THE PHASE DIAGRAM OF STRONGLY INTERACTING MATTER

I will discuss the importance of the nonuniform chiral condensate for the phase diagram of strongly interacting matter. In particular, the relation between quarkyonic matter and chiral density waves, the influence of the quark current mass, and the role of the magnetic field will be mentioned.

*Dr Andrzej Wereszczyński, (Uniwersytet Jagiellonski)*

### Applications of BPS Skyrme models to the baryonic and nuclei physics

BPS (Bogomol’nyi-Prasad-Sommerfield) type class of Skyrme model and its properties will be described. Mathematical properties of the model related to the stability of the model, symmetry properties, and integrability properties will be analyzed. The special emphasis will be given to the baryonic physics as described by the model.

*Dr Anar Rustamov (University of Frankfurt)*

### Probing the strongly interacting matter with NA61/SHINE at the CERN SPS

The results from the NA49 experiment on the onset of deconfinement will be presented and compared to the model predictions. Furthermore a new unbiased approach for event-by-event particle ratio fluctuations will be introduced. In this context the physics program of the NA61 experiment will be discussed.

*NA61/SHINE *

### Analysis/Calibration/Software Meeting

This week March 5-9 the NA61 Data Analysis Meeting of the CERN experiment NA61/SHINE (we are part of it) takes place in Wroclaw http://www.na61.ifd.uni.wroc.pl Everybody interested in experimental data analysis and data processing is also welcome. This is an unique oportunity to taste flavor and feel color of experimental kitchen. The special notice to Wednesday late afternoon session with theory-for-experiment lectures by Krzysztof Redlich and Thomas Klaehn.

*Daniel Zabłocki*

### Generalised Beth-Uhlenbeck description for the hadron-to-quark matter transition

A microscopic description of the equation of state for dense hadronic matter including the phase transition to quark matter is a long standing problem relevant for cosmology,heavy-ion collisions and the astrophysics of compact stars and supernovae. Traditional approaches construct a phase transition from separately given models for hadronic and quark matter phases. They cannot be trusted in the phase transition region and fail to predict a critical point in the phase diagram. Functional renormalization group approaches based on effective chiral Lagrangians improve the situation substantially but are not yet developed to describe hadrons as composite particles and thus cannot address the effects of bound state dissociation, such as the role of continuum correlations in the vicinity of the phase transition. We report recent progress in deriving and solving a generalised Beth-Uhlenbeck equation of state for quark matter with mesonic and baryonic correlations that does not suffer from these problems.

*Radosław Ryblewski MSc (IFJ, Kraków)*

### Highly-anisotropic and strongly-dissipative hydrodynamics and the early-thermalization puzzle

The recently formulated framework of highly-anisotropic and strongly-dissipative hydrodynamics (ADHYDRO) is used to study soft hadronic observables at the RHIC top energies. The transverse momentum spectra, HBT radii and directed and elliptic flows of different particle species are calculated for different initial anisotropy scenarios and compared to the experimental data. The results are discussed in the context of the early-thermalization puzzle.

*David Blaschke*

### Chiral condensate in a hadron resonance gas and a model for chemical freeze-out

The derivation of a formula for the chiral condensate in a hadron resonance gas is presented. A model for chemical freeze-out is presented where the melting of the chiral condensate in hot, dense hadronic matter leads to an increase in the hadronic radii facilitating fast chemical equilibration. The model predictions are in agreement with recent results from the beam energy scan program of the STAR experiment at RHIC Brookhaven.

*Davor Horvatic (University of Zagreb, Croatia)*

### Thermodynamics of the Polyakov-Dyson-Schwinger model

We review thermodynamic properties (pressure, energy and entropy density ...) of quark matter at finite temperature within the framework of the Polyakov-Dyson-Schwinger model. For the investigation we use a covariant, nonlocal separable model which allows to solve straightforwardly the Dyson-Schwinger equations for quark and meson propagators as well as to evaluate the partition function. Different scenarios are discussed by comparing different ansaetze for the dressed gluon interaction, including also the limit of the PNJL model, widely explored recently in discussing the low-energy QCD phase diagram.

*Gustavo Contrera (National University of La Plata, Argentina and University of Wroclaw, Poland)*

### Aspects of a non-local PNJL model with wave function renormalization

Results for thermodynamical properties of quark matter will be presented which are obtained within the framework of a two-flavor, non-local Polyakov-Nambu-Jona-Lasinio model which includes an interaction that produces the wave function renormalization (WFR) of the quark propagator. In the elaboration of the corresponding phase diagrams, special attention is devoted to the determination of the critical end points, by developing a system of equations that allows to calculate numerically the corresponding mean field values together with the precise location of the critical points. The values for critical exponents are examined. An outlook is given to the project pursued within a research visit at the University of Wroclaw.

*Dr. Gevorg Poghosyan (KIT Karlsruhe)*

### Advanced Support for Simulations in Astro- and Elementary Particle Physics

The adaptation of off-the-shelf scientific simulation codes into up-to-date HPC and distributed computing infrastructures leads to essential changes in the scientific simulation code. For integrating of scientific application software into modern e-Infrastructures, simulation laboratories (SimLab) are established at the Steinbuch Centre for Computing (SCC) of the Karlsruhe Institute for Technology. We have parallelized the Monte Carlo code CORSIKA to master the challenges of simulations of an Extensive Air Showers initiated by cosmic ray particles in the atmosphere at the highest energies of 100 Exa-eV (10^20 eV). During the past 20 years a code CORSIKA has been developed at KIT and became a standard instrument for scientists, studying the EAS induced by cosmic rays. But simulation of EAS induced by ultra high energy cosmic rays (UHECR) with energies as high as 1020 Exa eV with the present version of CORSIKA applicable for sequential runs only, could take decades on single computers. We have implemented workflow system for parallel execution of CORSIKA on distributed and supercomputing infrastructures. The preliminary test simulations on local cluster of Steinbuch Centre for Computing with 1500 cores, at initial energies of cosmic rays up to 1 Exa eV, allowed us to estimate computational needs and challenges for large scale, productive simulations at higher energies, as about 100k CPU hours per UHECR.

*1. Sanjin Benic (University of Zagreb), Croatia); 2. Sebastian Juchnowski (Wrocław)*

### 1. Phase structure and EoS of the PDSE model; 2. Solving self consistent integral equations on the GPU

Abstract 1.: We examine chiral and deconfinement phase transitions at T>0 in a Polyakov loop Dyson-Schwinger equation (PDSE) model. We evaluate the EOS at T>0 for a separable gluon interaction, first without the Polyakov loop variable. It is shown that the Polyakov loop removes the pressure instability. The robustness of the obtained results is examined for a class of separable models. Abstract 2: Over the last years progress has been made in solving Dyson Schwinger Equations (DSE) in medium. However, solving these selfconsistent integral equations with sophisticated interaction kernels requires significant numerical efforts and computation times, in particular in medium interations. I will address these problems and illustrate how parallel code evaluation on the computers GPU can reduce the computation time significantly.

*dr Stefan Typel (Helmholtzzentrum für Schwerionenforschung GSI mbH, Darmstadt)*

### Clusters in Nuclear Matter and Equation of State

Correlations are an essential feature of interacting many-body systems such as nuclear matter. They have an impact on the thermodynamical properties and on the composition since new particle species can be formed as bound states of the onstituents. This aspect and the knowledge of the equation of state is important for the application in the theoretical simulation of astrophysical phenomena like core-collapse supernovae. In this talk, a generalized relativistic mean-field (RMF) approach will be introduced that considers light nuclei up to the alpha particle as additional degrees of freedom and includes two-body scattering correlations in an effective way. The model is compared to the virial equation of state that is the model-independent low-density benchmark. Consistency relations between the RMF meson couplings and the scattering lengths are derived. The model successfully describes the formation and dissolution of light clusters in dense matter. It is also applied to neutron matter and compared to other approaches. An extension of the model to include heavy nuclei is proposed that requires in a first step to calculate the change of their bindung energies in dense matter.

*dr hab. Michał Spaliński (Uniwersytet Warszawski)*

### Holographic entropy currents from AdS/CFT

Relativistic hydrodynamics has been the focus of significant interest in recent years due its successful application to heavy ion collisions. Since quark gluon plasma is strongly coupled in the applicable regime it is interesting to consider the hydrodynamics of N=4 supersymmetric Yang-Mills theory, where a calculable dual description exists and allows a derivation of the hydrodynamic framework. After some introductory review, I will discuss the construction of the hydrodynamic entropy current on both sides of AdS/CFT duality highlighting the question of ambiguities arising at second order in the gradient expansion.

*Dr Olaf Kaczmarek (University Bielefeld)*

### Hadronic Correlation and Spectral Functions in the QGP

I will discuss properties of hadronic excitations at high temperature by investigating hadron correlation functions for light as well as charm quarks in the deconfined phase of quenched QCD. We have performed a systematic analysis of the influence of cut-off effects on light quark meson correlators at T=1.5 T_c using clover improved Wilson fermions on quenched gauge field configurations. We check that finite volume effects are small compared to the significant cut-off dependence observed in the correlation functions. The continuum extrapolation of these correlators are seen to be well under control for distances 0.2 < τ T < 0.5. We discuss consequences for the determination of hadronic spectral functions and the analysis of their low energy structure. In the light quark sector this leads to the determination of the dilepton rates and an estimate on the electrical conductivity. For charm quarks we discuss the determination of heavy quark diffusion constants and estimates on the dissociation of charmonium states in the plasma.

*Carlos Pena*

### Quantum mechanical model for J/psi suppression in the LHC era

We discuss the effects of screening and absorption in a strongly correlated plasma medium on the quantum mechanical evolution of quarkonia states within time-dependent harmonic oscillator model with complex oscillator strength. We compare the results with data for R_AA/R_AA(CNM) from RHIC and SPS experiments and extrapolate to the LHC domain where first data have appeared recently, but still no cold nuclear matter (CNM) effects are analyzed. We discuss the peculiar temperature dependence of real and imaginary parts of the oscillator strength in view of the recently found X(3872) state in the charmonium spectrum and possible regeneration effects in the kinetics of charmonium production in heavy-ion collisions.

*Rafał Łastowiecki*

### Systematic exploration of hybrid EoS with color superconducting quark matter and the mass constraint from PSR J1614-2230

We discus the impact of the mass measurement of PSR J1614-2230 on modeling hybrid compact stars with color superconducting quark matter cores described by the Nambu--Jona-Lasinio model. We derive constraints on the allowed parameters ranges and present possible hybrid star configurations in this framework. Additionally, we discuss the corresponding hybrid equation of state for symmetric matter in view of the flow constraint from heavy-ion collisions.

*Jakub Jankowski*

### Polarization loop at finite temperatures and densities

I show standard evaluation of one loop polarization function in QED at finite temparatures and densities. Recent extension of calculation with obtained result will be shortly mentioned.

*Ludwik Turko*

### Heavy ions news

Two recent large international conferences - Quark Matter 2011 (Annecy, June 2011) and Strangeness in Quark Matter 2011 (Cracow, September 2011) were devoted mainly to new experimental results from new generation experiments performed in LHC-CERN (ALICE, CMS) and RHIC-Brookhaven (STAR, PHENIX). Main conclusions of these conferences will be presented. A discussion about the 2011/2012 activity of Elementary Particle Theory Division is also expected.

*Niels-Uwe Bastian (Universitaet Rostock)*

### Different approaches to the EoS of dense nuclear matter

Equations of States (EOS) are important prerequisites to predict the behavior of nuclear systems. Using measured properties of nuclear systems as input, various models can be designed that determine the tthermodynamic properties of nuclear matter in a wide region of density, temperature, and asymmetry. Different models are onsidered, and the resulting properties are compared. In particular, the region of phase instability and neutron star properties are investigated.

*mgr Jakub Jankowski*

### Inhomogeneous phases in cold, dense Holographic QCD - cont.

A short review of the Sakai-Sugimoto model of Holographic QCD will be given with special emphasis on the phase structure emerging from it. Recent investigations show that spatially inhomogeneous phases should dominate at certain values of temperature and baryochemical potential. For cold and dense matter this may provide a dual holographic description of the Quarkyonic Chiral Spiral.

*mgr Jakub Jankowski*

### Inhomogeneous phases in cold, dense Holographic QCD

A short review of the Sakai-Sugimoto model of Holographic QCD will be given with special emphasis on the phase structure emerging from it. Recent investigations show that spatially inhomogeneous phases should dominate at certain values of temperature and baryochemical potential. For cold and dense matter this may provide a dual holographic description of the Quarkyonic Chiral Spiral.

*dr Thomas Klähn*

### Light Quarks and Heavy Neutron Stars

Recently, the mass of pulsar PSR J1614 has been determined very precisely with a value of 1.97pm0.04 solar masses. This makes it the heaviest ever observed neutron star. Moreover, this result puts tight constraints on a realistic equation of state for cold and dense matter. I will discuss to what extent this affects the possible existence of quark matter in neutron stars, what it tells us about the quark matter quation of state, and whether we can learn something about the QCD-phase transition in heavy ion collisions.

*Carlos Pena*

### Quantum evolution of quarkonia and J/psi suppression data

A generalization of Matsui formula for quarkonium production will be presented as well applications of it with different quantum time evolution models.

*Hovik Grigorian, Yerevan State University*

### Cooling of the neutron star in Cassiopeia A

We show that the cooling data for the youngest known neutron star (NS) in our galaxy, observed over the past 10 years in the center of the supernova remnant Cassiopeia A (Cas A) can be successfully explained within the Medium Modified Superfluid Cooling (MMSC) scenario. The MMSC scenario developed by us 7 years ago is explained and it is shown that the rapid cooling of Cas A lies in the era when the isothermal regime of the NS is established so that a very sensitive dependence on the mass and the heat conductivity of NS matter results. We discuss the effect of a possible color superconducting quark matter core on the mass of Cas A and discuss consequences for NS phenomenology.

*prof. David Blaschke*

### Chiral condensate and chemical freeze-out

We consider a chemical freeze-out mechanism which is based on a strong medium dependence of the rates for inelastic flavor-equilibrating collisions based on the delocalization of hadronic wave functions and growing hadronic radii when approaching the chiral restoration. We investigate the role of mesonic (pion) and baryonic (nucleon) fluctuations for melting the chiral condensate in the phase diagram in the (T,mu)-plane. We apply the PNJL model beyond mean-field and present an effective generalization of the chiral perturbation theory result which accounts for the medium dependence of the pion decay constant while preserving the GMOR relation. We demonstrate within a schematic resonance gas model consisting of a variable number of pionic and nucleonic degrees of freedom that within the above model a quantitative explanation of the hadonic freeze-out curve and its phenomenological conditions can be given.

*Rafał Łastowiecki*

### Schladming Winter School - Renormalization Groups

I will briefly discuss applications of renormalization groups (RG) theory for solving hot problems in modern physics. In particular: nuclear matter properties, approximate solutions for QCD-like theories, non-equilibrium RG description of initial conditions in HIC and early Universe and finally RG approaches to quantum gravity.

*Carlos Andres Peña Castañeda*

### Matsui formula and anomalous charmonium suppression in hot medium

I will show that a formula for charmonium suppression obtained by Matsui in 1989 can be applied to describe J/psi suppression in heavy-ion collisions at CERN-SPS and RHIC. Last results for two different c-cbar time evolutions will be presented: (1) A time-dependent harmonic oscillator, (2) A QQbar in a hot medium of photons and fermions.

*Rafał Łastowiecki*

### EoS and phase diagram in a modified PNJL model

We will present constraints on the equation of state of cold, dense matter following from observations of the compact stellar objects, with particular emphasis on mass-radius relations for compact stars. The analysis will be performed within the PNJL framework for quark matter, supplemented with selection of hadronic equations of state. We will discuss the influence of KMT interaction term and modifications of Polyakov loop potential by term dependent on chemical potential on the equation of state of quark matter. We will discuss the new measurements of mass of pulsar PSR J1614-2230 of 2 solar masses and an importance of this measurement on on straining the equation of state of cold dense matter. Extra remark: the seminar starts at 10:00 sharply

*dr Krzysztof Graczyk*

### Neutrinos - Neverending Story

In the first part of the seminar I will discuss the basic neutrino properties. Then the latest neutrino oscillation experimental results will be briefly presented. Eventually, I will focus on the problems which occur in the investigation of the neutrino-nucleon/nuclei interaction.

*prof. David Blaschke*

### The dense matter EoS from compact stars

After a short introduction to modern observations of compact stars (CS), which concern different astrophysical objects such as pulsars, double neutron stars, accreting low-mass X-ray binaries etc., we consider the plans to extract the cold dense equation of state (EoS) from CS mass and radius measurements. In the near future the NASA International X-ray Observatory (IXO) project shall deliver such data with 5% accuracy and thus provide a benchmark for the T=0 EoS which will play a similar role as the zero-density EoS from Lattice QCD. We will outline the current status of research towards a quantum field theoretical approach to the EoS of dense quark matter with special emphasis on color superconducting quark matter phases and the contributions from our group which is part of the research networking programme "The New Physics of Compact Stars - CompStar" (2008-2013) of the European Science Foundation.

*Ludwik Turko*

### Division of Elementary Particle Theory 2010/2011

The meeting will be devoted to the organisation of our seminar in the new academic year, plans for the future and retrospective view for the 2009/2010 past. Everybody related to the Division is welcomed. Some refreshments are also expected.

*Andrey Radzhabov, Institute for System Dynamics and Control Theory, Irkutsk, Russia*

### Nonlocal PNJL model beyond mean field

A nonlocal chiral quark model is consistently extended beyond mean field using a strict $1/N_c$ expansion scheme. The parameters of the nonlocal model are refitted to the physical values of the pion mass and the weak pion decay constant. It is also found that the $1/N_c$ corrections lead to a lowering of the temperature of the chiral phase transition in comparison with the mean-field result. On the other hand, near the phase transition the $1/N_c$ expansion breaks down and a non-perturbative scheme for the inclusion of mesonic correlations is needed in order to describe the phase transition point.

*Craig D. Roberts (Argonne Natl. Lab., USA)*

### Aspects of QCD Theory and Application

I will explain that the chiral-limit vacuum quark condensate is qualitatively equivalent to the pseudoscalar meson leptonic decay constant in the sense that they are both obtained as the chiral-limit value of well-defined gauge-invariant hadron-to-vacuum transition amplitudes that possess a spectral representation in terms of the current-quark mass. Thus, whereas it might sometimes be convenient to imagine otherwise, neither is essentially a constant mass-scale that fills all spacetime. This means, in particular, that the quark condensate can be understood as a property of hadrons themselves, which is expressed, for example, in their Bethe-Salpeter or light-front wavefunctions. In addition, using the pion elastic electromagnetic form factor, I will illustrate how an interplay between modern experiment and theory can be used to chart the interaction between light-quarks at long range.

*Rafał Łastowiecki*

### EoS and phase diagram in a modified PNJL model

We will present constraints on the equation of state of cold, dense matter following from observations of the compact stellar objects, with particular emphasis on mass-radius relations for compact stars. The analysis will be performed within the PNJL framework for quark matter, supplemented with selection of hadronic equations of state. We will discuss the influence of KMT interaction term and modifications of Polyakov loop potential by term dependent on chemical potential on the equation of state of quark matter.

*Jakub Jankowski*

### Quarkyonic Matter: basic ideas and recent developments -- cd

In this seminar I will review properties of QCD with large number of colors and the way it led to the Quarkyonic Matter phase, in which confinement cooperates with chiral symmetry restoration. Recent investigations along this line have shown that for large chemical potentials the Fermi sea is unstable against formation of a spatially nonuniform condensate which breaks chiral symmetry but in a different way than in vacuum. The possibility of Quarkyonic Matter in the 't Hooft model will be shortly discussed.

*Jakub Jankowski*

### Quarkyonic Matter: basic ideas and recent developments

In this seminar I will review properties of QCD with large number of colors and the way it led to the Quarkyonic Matter phase, in which confinement cooperates with chiral symmetry restoration. Recent investigations along this line have shown that for large chemical potentials the Fermi sea is unstable against formation of a spatially nonuniform condensate which breaks chiral symmetry but in a different way than in vacuum. The possibility of Quarkyonic Matter in the 't Hooft model will be shortly discussed.

*Carlos Pena*

### Quantum harmonic oscillator model for J/psi suppression in SPS and RHIC

In this work we consider a quantum-mechanical model for the evolution of the charmonium state in a partially deconfined medium. We use a harmonic oscillator potential with complex oscillator frequency representing screening and absorption effects. Applying this model to J/psi production in heavy-ion collisions at CERN-SPS and RHIC we show that such a model can give a description of the behavior of the measured J/psi yield over the expected Cold Nuclear Matter effects RAA=RCNM, as a function of the charged particle number per pseudo-rapidity in the central rapidity region.

*dr Stefan Typel - GSI Helmhotz Zentrum, Darmstadt*

### Heavy nuclei and clusters in nuclear matter

At densities below saturation and not too high temperatures, nuclear matter is a spatially inhomogeneous system composed of heavy nuclei immersed in a sea of nucleons and light clusters. Thermodynamical properties and the composition of the matter are strongly affected by the formation of clusters. In this talk the description of such a system based on a generalized relativistic mean-field model is presented. This approach allows a smooth interpolation between the low-density phase dominated by few-body correlations and the homogeneous phase above saturation where mean-field concepts are applicable.

*Ludwik Turko*

### Workhorses of high energy physics

There are standard computational tools used in the growing high energy physics community. They appeared more and more popular as new great experimental collaborations started their activity. I’m going to make a short review of the present situation, with the special emphasis on implementing those packages. They work quite well on the present PC level and give a possibility of data analysis, data presentation and also of comparing brilliant theoretical ideas with nasty experimental data. The standard framework for such applications is the ROOT package. One can implement within this a lot of particular, more specialized packages as e.g. THERMUS or THERMINATOR for heavy ion physics. There is also a devoted Linux system – Scientific Linux (SCL) – maintained by CERN and Fermilab, suited particularly for high energy physics demands.

*dr Yuri Shtanov, Bogolyubov Institute for Theoretical Physics, Kiev*

### Statistical anisotropy in the inflationary universe

Cosmological inflation remains to be a unique theory of generation of plausible initial conditions in the early universe. In particular, it generates the quasiclassical perturbations with power spectrum determined by the fundamental principles of quantum field theory. After the end of inflationary epoch, such perturbations serve as primeval seeds for the formation of large-scale structure (galaxies and galactic clusters) in the universe. In this talk, we pay attention to the fact that the quasiclassical perturbations permanently generated at early stages of inflation break homogeneity and isotropy of the cosmological background. The evolution of the small-scale quantum vacuum modes then proceeds on this inhomogeneous background. As a result, the power spectrum of primordial perturbations develops statistical anisotropy, which can manifest itself in the observable large-scale structure and cosmic microwave background. The effect is predicted to have almost scale-invariant form dominated by a quadrupole and may serve as a non-trivial test of the inflationary scenario. Theoretical expectation of the magnitude of this statistical anisotropy depends on the assumptions about the physics in the trans-Planckian region of wavenumbers. Part of the talk will be devoted to the discussion of this trans-Planckian issue in cosmology.

*Jakub Jankowski*

### Holographic Superconductors

In this seminar I will review latest developments in constructing models for csuperconducting systems based on the AdS/CFT correspondence. This may result in new insights in cuprate high T_c superconductors physics which by now is poorly understood. Means of obtaining condensates and conductivities will be presented.

*mgr Jakub Jankowski*

### CERN Winter School - an overview

In February I have been participating in the CERN winter School on Supergravity, String Theory and Gauge Theories. A general overview of the thematics will be given with emphasise on the recent applications of AdS/CFT correspondence to condensed matter systems.

*Daniel Zablocki*

### Nonlocal RMF Calculations for Nuclear Matter

We show some preliminary results for Relativistic Meanfield (RMF) calculations for Nuclear Matter including different scalar and vector channels. In particular we discuss the influence of formfactors on the thermodynamics of Nuclear Matter.

*Prof. David Blaschke*

### Towards an Equation of State for quarkyonic matter

Quarkyonic matter is , characterized by (approximate) chiral symmetry (almost massless quarks) and confinement so that it shall consist of hadrons with (almost) identical masses for chiral partners. This situation is expected to occur for matter at high densities above nuclear matter density and for temperatures below the deconfinement temperature of about 180 MeV, thus most relevant for compact star interiors, supernova collapse simulations and for future heavy-ion collision experiments as FAIR-CBM, low-energy RHIC or NICA-MPD. For those applications one would need an equation of state (EoS) for quarkyonic matter. In this talk we review the present status of our research towards a microscopic description of the EoS for quarkyonic matter.

*Prof. Ludwik Turko*

### Hot and Dense Nuclear Matter Workshop

Department of Physics of University Cape Town organized, in the second half of February, the workshop devoted to properties of the dense nuclear matter. Three members (D.B., K.R., L.T.) of our Division of Theory of Elementary Particles were among lecturers of the workshop. A summary of this workshop will be presented.

*Prof. Krzysztof Redlich*

### Quarkyonic Matter and Chiral Symmetry Breaking

A new phase structure of hadronic matter - Quarkyonic Matter - was suggested by L. McLerran and R. Pisarski some times ago. This matter would be gluon dominated in the deconfined phase and baryon/quark dominated in the confined phase. New results, will be presented, supporting that hypothesis. Results are based on NJL type model calculations.

*Jakub Jankowski*

### QGP formation

In December 2008, I participated in the school in Torino (Italy) devoted to the present status of our understanding of the Quark Gluon Plasma formation in Heavy Ion Collisions. The picture emerging from the SPS and RHIC experiments was explained in the context of forthcoming new experiments at the CERN LHC. I give a short personal overview over the school and material presented there.

*dr Dariusz Grech*

### Detrended Fluctuation Analysis (DFA) and Random Matrix (RM) approach in detection of signals immerse

Econophysics appearance more than a decade ago raised new hope to understand better the existing technologies used in complex systems and to construct basically new ideas in complexity. It is because the financial market is often considered as the largest and most complicated complex system ever built by human. Indeed, a junction between physics and econophysics has become very fruitful. It produced many new approaches describing complexity and significantly modified the existing ones giving a positive feed-back with physics. Detrendisation techniques and random matrices are well written into them. First, I will focus my lecture on the general outlook of DFA and RM techniques applied in science so far. Then, we shall consider their interesting modifications giving possibility to detect any distortion of long-range dependence from the assumed pattern in time series. In particular, signals immersed in noise can be well detected this way. Application to real physical data coming from existing detector of weak signals (Nautilus gravitational wave experiment) will be presented to show the strength of new methods for signal detection and its treatment.

*dr Krzysztof Graczyk*

### The Nucleon Form Factors

The nucleon form factors have been a subject of intensive theoretical and experimental studies for many years. These functions describe the internal structure of the proton and neutron. The electromagnetic form factors are mainly obtained from elastic electron-nucleon and electron-nucleus scattering data. Q2 dependence of the axial form factor is mainly extracted from quasielastic neutrino-nucleon and neutrino-nucleus scattering data. The strange nucleon form factors, the most unknown, are obtained from parity-violating electron-nucleus as well as from elastic neutrino-matter scattering measurements. The newest electron and neutrino scattering experiments provide us with the higher precision data, and then with electromagnetic and axial form factors, which seem to have different Q2 dependence than the ones obtained from old analyses. In this talk I will focus on the discrepancy between electromagnetic form factors obtained via Rosenbluth separation (e.g. form JLab) and the ones extracted from polarization data (JLab, BLAST, Maintz). It will be shown that Two Photon Exchange correction can explain the problem. For all electromagnetic form factors I will present results of my analyses of the newest experimental data -- the fits of form factors with their uncertainties. The knowledge of the uncertainties plays a crucial role for the extraction of the strangeness of the nucleon (elastic neutrino-nucleon scattering data).

*1. dr hab Dariusz Prorok 2. mgr Carlos Pena*

### 1. J/Psi absorption in a multi-component hadron gas: from SPS to RHIC;2. Quantum Harmonic Oscillato

1. A model for anomalous J/Psi suppression in high energy heavy ion collisions is presented. As the additional suppression mechanism beyond standard nuclear absorption inelastic J/Psi scattering with hadronic matter is considered. Hadronic matter is modeled as an evolving multi-component gas of point-like non-interacting particles. The longitudinal and transverse expansion of the gas is taken into account. It is shown that under these conditions the resulting J/Psi suppression pattern agrees well SPS and RHIC data. 2. The Dynamical origin of the J/psi suppression in ultrarelativistic nucleus-nucleus collisions is studied focusing on the formation mechanism of heavy quark bound state. An interesting mechanism proposed by T. Matsui makes use of a schematic harmonic oscillator model for the intermediate and final cbar bound states where the distortion of charmonium formation amplitude is due to the deconfined enviorement. I will present a short introduction to this quantum mechanical model and its possible contribution to the understanding of J/psi suppression in NA50 and NA60 experiments.

*mgr Daniel Zabłocki *

### From quarks to dileptons - scope of a PhD project

We develop a formalism for a systematical treatment of quark matter including color superconducting phases above the meanfield approximation. The roadmap for the PhD project is presented. I will show the status of my own investigations as well as compare them to the status in the field. The main steps and challenges are pointed out when going towards a calculation of the impact on e.g. the dilepton spectrum or the EoS for quark matter. Extensions of this formalism to HIC phenomenology as well as Compact Star physics are discussed as well.

*dr Artur Ankowski*

### Nuclear effects in neutrino interactions

In neutrino physics one compares theoretical predictions to experimental results using Monte Carlo simulations. Because in detectors neutrinos interact with atomic nuclei, uncertainties come mainly from nuclear effects. Typically, Monte Carlo generators are based on the Fermi gas model. From electron scattering one knows, however, that such approach can be treated only as the first approximation. Clearly better description of nucleus can provide its spectral function, describing the energy and momentum distribution of nucleons that compose the nucleus. It is important due to crucial role of precision in future experiments such as MINERvA and T2K. I want to present results calculated using the spectral functions of calcium and argon, obtained during my PhD studies. I will show that they allow for very accurate description of nucleus in electron scattering. Some of the electron data correspond kinematically to ~1-GeV neutrino interactions, what allows for indirect testing accuracy of modeling nuclear effects in the neutrino case. The presented description is going to be a part of the NuWro generator.

*Krzysztof Redlich, Ludwik Turko*

### Hot dense hadronic matter

We are going to present problems and results related to the signatures of critical bevaviour expected in the hot dense hadronic matter formed in the ultrarelativistic heavy ion collisions. These are: lattice QCD methods, chiral symmetry breaking in the effective models, heavy quarkonium suppression, dileptons nad direct photons signals

*Prof. Jan Sobczyk*

### Activity of the Wroclaw Neutrino Group in 2008

I will provide a review of research done recently by WNG (Wroclaw Neutrino Group). This includes: development of NuWro - Wroclaw Monte Carlo generator of events, investigation of Delta excitation region, construction of medium nuclei spectral functions. Plans for the future will be described as well.

*David Blaschke*

### Heavy quarkonia in heavy-ion collisions

Starting from a historical perspective on both, theoretical and experimental developments, the basic concepts for describing the phenomena summarized as "anomalous quarkonia suppression" are developed. The theoretical approach is built on information for the in-medium modification of hadronic properties obtained from Lattice QCD studies, as well as from effective models. We emphasize the powerful techniques of thermodynamic Green functions (T-matrices) in order to derive the necessary input quantities for a description of heavy quarkonia suppression and regeneration within a kinetic theory. The perspectives from future experiments on charmonium and bottomonium production for our understanding of hadronic matter under extreme conditions are discussed.

*Jean Cleymans, CapeTown - RPA*

### Rapidity dependence of thermal parameters at SPS and RHIC

The rapidity dependence of the thermal parameters $T$ and $mu_B$ has been determined for SPS and RHIC and shows a systematic behavior towards an increase in $mu_B$ away from mid-rapidity.

*Daniel Zabłocki*

### BEC-BCS crossover in the NJL model of QCD

The phenomenon of BEC-BCS crossover occurs in dense, strongly correlated Fermi systems and has recently been discussed for cold dense quark matter systems. We consider this phenomenon for the two- and three-color NJL model with scalar-pseudoscalar mesonic and scalar diquark correlations in dependence on the diquark coupling strength. The effect of the inclusion of the vector-axial vector meson sector is investigated. For applications to compact stars the constraint of color- and electric neutrality need to be considered while for heavy-ion collisions, an extension to finite temperatures is necessary.

*Dr. Daniel Gomez Dumm, La Plata, Argentina*

### Phase diagram of neutron star quark matter in nonlocal chiral models

We study the phase diagram of two-flavor quark matter under neutron star constraints for the case of nonlocal, ovariant quark models within the mean field approximation. At intermediate densities, it is seen that various low-temperature quark matter phases can occur. On the other hand, critical temperatures at zero chemical potential are found to be in better agreement with lattice QCD results than the prediction of the standard local NJL model.

* Carlos Andrés Peña Castañeda*

### CHEMICALS POTENTIAL IN THE ELECTROWEAK STANDARD MODEL

In the context of thermal quantum field theory are introduced three chemical potentials associated to the three conserved currents in the Electroweak Standard Model: electromagnetic, weak neutral and lepton number. The neutrality condition over electromagnetic and weak neutral charges is calculated by mean thermodynamic potential. The calculations are done using the mean field approximation at high temperature limit.

*Prof. Jan Sobczyk*

### What is the number of neutrinos ?

Few days ago the results of the MiniBoone experiment were published and the question about the number of neutrino flavors was answered. In the seminar several issues related to the MiniBoone experiment will be covered in a rather informal way.

*dr Marcin Piątek*

### The AdS/CFT Correspondence and its Applications. Part II: From AdS/CFT Correspondence to Heavy Ion:

There was a mistake in the previous message. Seminarium will take place on TUESDAY, April 3. In the context of the AdS/CFT correspondence we will discuss recently proposed by E. Shuryak and S. Lin (hep-ph/0610168) the dual gravity (string theory) description of a relativistic heavy ion collision (RHIC) in a strongly coupled N=4 Super Yang-Mills theory. Also a very brief review of the another RHIC scenarios and its gravity duals will be mentioned.

*Roberto Anglani - INFN and University of Bari *

### Inhomogeneous color superconductivity in the core of compact stars

We consider the general aspects of color superconductivity (CSC) with some remarks on the astrophysical consequences in the physics of compact stars. In particular the possible effects of the presence of an "inhomogeneous" CSC matter (named LOFF by names Larkin-Ovchinnikov-Fulde-Ferrell) in the core of a neutron star (NS) will be discussed. Finally we show some results concerning neutrino emissivity and specific heat of a toy model of NS with a core of LOFF matter.

*dr Marcin Piątek*

### The AdS/CFT Correspondence and its Applications; Part I: An intro to the Maldacena's duality

The AdS/CFT correspondence is one of the most significant results that string theory has produced. It refers to the existence of amazing dualities between theories with gravity and theories without gravity, and is also sometimes referred to as the gauge theory/gravity correspondence. The prototype example of such correspondence, as originally conjectured by Maldacena, is the exact equivalence between type IIB string theory compactified on 5-dimensional anti-de Siter space * 5-dimensional sphere, and 4-dimensional conformal N=4 supersymmetric Yang-Mills theory. The AdS/CFT correspondence is an example of a weak/strong coupling duality and can be use as a tool to study strongly interacted gauge theories or non-perturbative stringy physics. Another particularly fascinating aspect of the AdS/CFT correspondence is that it is a concrete realization of a Holographic Principle, which states that there should be a lower dimensional non-gravitational representation of degrees of freedom of any quantum theory of gravity. In this talk, which is a second part of a three-part seminar devoted to the AdS/CFT correspondence and its applications, we give a brief introduction to the Maldacena's duality, describe some tests, and mention some resent developments.

*dr Marcin Piątek*

### The AdS/CFT Correspondence and its Applications; Part I: An introduction to the Maldacena's dua

The AdS/CFT correspondence is one of the most significant results that string theory has produced. It refers to the existence of amazing dualities between theories with gravity and theories without gravity, and is also sometimes referred to as the gauge theory/gravity correspondence. The prototype example of such correspondence, as originally conjectured by Maldacena, is the exact equivalence between type IIB string theory compactified on 5-dimensional anti-de Siter space * 5-dimensional sphere, and 4-dimensional conformal N=4 supersymmetric Yang-Mills theory. The AdS/CFT correspondence is an example of a weak/strong coupling duality and can be use as a tool to study strongly interacted gauge theories or non-perturbative stringy physics. Another particularly fascinating aspect of the AdS/CFT correspondence is that it is a concrete realization of a Holographic Principle, which states that there should be a lower dimensional non-gravitational representation of degrees of freedom of any quantum theory of gravity. In this talk, which is a first part of a three-part seminar devoted to the AdS/CFT correspondence and its applications, we give a brief introduction to the Maldacena's duality, describe some tests, and mention some resent developments.